Protactinium
Symbol: Pa

Atomic Number: 91
Atomic Weight: 231.036
Protons: 91
Neutrons: 140
Electrons: 91
Actinide Series

Brief Description:
Protactinium is brightly metallic in appearance, and can maintain this appearance (resisting oxidation) for some time. Protactinium is super-conductive below 1.4 kelvin. The element is extremely toxic, and requires supervision and care equal to that of plutonium. It is one of the rarest and most expensive of the naturally-occurring elements, and is highly radioactive.